三峡二期上游围堰防渗墙施工

Construction of impervious wall for second stage upstream cofferdam of Three Gorges Project

三峡二期上游围堰防渗墙施工工期紧,墙体高度大,围堰防渗基础地质条件复杂,施工难度大,通过引进液压双轮铣、液压抓斗及全液压工程钻机等先进设备,采用铣、抓、砸、钻孔预爆、聚能爆破、预灌浓浆等施工工艺,克服了砂卵石漏失层、块球体钻进、陡坡段嵌岩等一系列困难,大大提高了围堰防渗墙施工进度,确保了围堰防渗墙的施工安全.

In consideration of some factors in construction of the impervious wall for the second stage upstream cofferdam of the Three Gorges Project, such as the short construction period, high wall, complicated geologic condition of the foundation of the impervious wall, and great difficulties in the construction, some advanced facilities are imported from abroad, and some construction techniques are adopted, including milling, grabbing, tamping, bore-blasting, energy-gathering blasting, and pre-heavy grouting. By use of the techniques, some technical difficulties are overcome, such as the prevention of leakage through the sand and gravel layer, drilling into spheric blocks, rock embedment of steep slope, and so on. Hence the techniques greatly accelerate the construction and ensure its safety.